1. Field of the Invention
This invention belongs to the field of synthetic organic chemistry, and provides a process for preparing 6-t-alkyl-3-pyridazinones which are useful intermediates for N-pyridazinylbenzamide herbicides. The tertiary alkyl group of the compounds is quite bulky and has a strong steric effect, which impedes or, in some cases, substantially prevents the closure of the pyridazine ring by conventional methods.
2. State of the Art
The formation of 3-pyridazinones from 3-acyl-2-propenoic acids and hydrazine is a known process. It is quite effective for preparing compounds wherein the acyl group is benzoyl or the like, as shown by West German application No. 2,435,244. When the acyl group is a tertiary alkanoyl group, however, the cyclization does not go smoothly to form the desired pyridazinone, but instead gives a complex product, believed to be a dipyrazolopyrimidinedione.